The amount of milk sold each day by a grocery store varies according to the Normal distribution with mean 126 gallons and standard deviation 10 gallons. – a. On one randomly-selected day, what is the probability that the grocery store sells at least 137 gallons? Round your answer to 4 decimal places, if needed. – b. Over a span of 7 days (assuming the randomness requirement is not violated), what is the probability that the grocery store sells an average of at least 137 gallons? Round your answer to 4 decimal places, if needed.